Rhythm calculator



June 27, 1950 P. MORSE RHYTHM CALCULATOR 5 Sheets-Sheet l Filed NOV. 18, 1946 f4 ff/ f4 91011 IZI3@15H6[7!81'22021222524 E425 L Moes/'5 June 27, 1950 P. L. MORSE .amm CALCULATOR 5 Sheets-Sheet 2 Filed Nov. 18, 1946 /M/f/v'me 10142K L .M0255 June 27, 1950 P. l.. MORSE 2,513,196

RHYTHM CALCULATOR Filed Nov. 18, 1946 s sheets-sheet s gli June 27, 1950 P. L.. MORSE 2,513,196

RHYTHM CALCULATOR Filed NOV. 18, 1946 5 Sheets-Sheet 4 3mm@ 2T@ W50 al-. MORSE @$13,396

RHYTHM CALCULATOR Filed Nov. 18, 1946 5 Sheets--Sheetv 5 INVE/vro ,942e L /Vaesf //Fi6 ,32; www

Patented June 27, 1950 UNITED STATES PATENT GFFICE RHYTHM CALCULATOR Park L. Morse, Emporia, Kans.

Application November 18, 1946, Serial No. 710,574`

This invention relates to calculators, and more particularly to calculators for ascertaining the fertile and infertile periods of Women during their menstrual cycles.

The rhythm system of birth control is based upon the following three factors:

l. Ovulation of a female occurs only 'within a period of twelve to sixteen days preceding the start of her next menstrual period, this period of ovulation being independent of the length of time of mentrual 4liow and the length of the menstrual cycle.

2. The ovum can be fertilized only within 24 hours following ovulation.

3. The ovum can be fertilized only -by spermau tozoa not older than 72 hours.

Accordingly, it follows that fertilization of the ovum ican take place only as a result of coitus taking place sometime within an interval of eight days lying ibetween the 11th and 19th days preceding the start of the next subsequent menstruation. For ready reference, the interval during which ovum fertilization can occur will be referred to hereinafter as the conception period.

Since there is a variation from month to month in the menstrual cycle of many normal Women, it is impossible to predict accurately the iirst day of the next succeeding menstruation. It, therefore, becomes necessary to include with the conception period of any particular female the maximum number of days which her menstrual period is known to vary. For example, if a female has a menstrual cycle varying from 28 to 30 days, the possible maximum conception period would be days rather than the 8 days of a female who has a regular menstrual cycle. The first possible day of her conception period would then occur 19 days preceding her next menstruation, calculated on the `basis of the shortest menstrual cycle; and the last possible day of her conception period would end on the 11th day preceding her next menstruation, calculated on the basis of her longest menstrual cycle.

The foregoing biological phenomenon has been set forth in my application for Calculaton Ser. No. 662,440, led April 16, 1946, which describes and claims a device for precisely detere mining the calendar interval constituting the possible conception period of any specified woman, making due allowance for variations in her menstrual cycle, theinterval Within this period when coitus is most likely to result in conception, and for indicating the possible commence- 2 Claims. (Cl. 23S-86) 2 ment date of her next menses and the duration' of the next menstrual cycle.

An object of the present invention resides in the provision of a calculator' of the foregoing general nature which s much simpler for the average person to operate, and which offers greater assurance against its inadvertent misuse and the obtaining of erroneous indicated results.

A further object of the invention lies in the provision of a relatively compact calculator based on. the rhythm system, which, despite its compactness, embodies an annual calendar and one or more menstrual cycle scales with comparatively Widely spaced daily intervals or indicia thereon, lending itself to more accurate setting and reading.

The invention possesses other advantageous features, some of which, together with the foregoing, will be set forth at length in the following description of several forms of the invention, which have been selected for illustration in the drawings accompanying and forming part of the present specification. In said drawings, although several forms of the invention are shown, it is to be understood that it is not limited to such forms, since the invention as set forth in the claims may be embodied in a plurality of other forms.

Referring to the drawings:

Fig. l is an isometric View of a completely assemloled rhythm calculator embodying the invention.

Fig. 2 is a diagrammatic front elevation on an enlarge-d scale and in a single plane of the viewing portion of the calculator.

Fig. 3 is a cross-section taken generally along the line 3--3 of Fig. l.

Fig. 4 is a section taken generally along the line 4 4 of Fig. 3.

Fig. 5 is a partial section taken along the line 5 5 on Fig. 4.

Fig. 6 is a front elevation in a single plane of part of the calendar tape.

Figs. 7 and 8 are exploded views of parts of the calculator mechanism.

Fig. 9 is a top plan view of a modified form of the invention.

Fig. l0 is a front elevation of the calculator disclosed in Fig. 9.

Fig. l1 is a Apartial section taken along the line l l--l I on Fig. 9.

Fig. l2 is a top plan View of another modified form of the invention.

Fig. 13 is a front elevation of the calculator disclosed in Fig. 12.

sprocket I8 is secured. The sprocket has two-Iy longitudinally spaced rows of sprocket teeth. I9.

engageable in spaced openings ZIJ of the endless, flexible calendar tape I having 365 equal. difvisions thereon to represent the. number of days in a normal calendar year. The tape openings 20 are spaced apart a distance equal to the `zpitcht of the sprocket teeth I9. This tape rides along the..exterior .of the forward housing-wall IZa be-A tween the openings I3, vHtthrough which. it extends for passage arounda roller 2l rotatably mounted on a vertical, stationary pin 22 suitably secured` tothe baseII of .the housingadjacent its rearward wall .I2b, and around a plurality of circularly. spaced rollers 23a, 23h arranged in inwarcland outward spiral fashion withrespect to thecentral sprocket IS.- The rollers 23a, 2313 are rotatably mounted on vertical pins 2e suitablyv secured, as by riveting, to the basef25 of a roller rack 2t having a central opening 21 surrounding the bearing socket IE'and resting on. the housing base I I, to which it is non-rotatably.

secured in the manner to bedescribed.

It is apparent that the endless tape I5 proceeds.

from the exterior ofthe forwardwall IZath'rough oneof the wall openings I3,. around the housing roller .2 I. and the exterior of vone set of rackrollers. 23m. progressing inwardly around these rollers in.. spiral fashion until it passes over the central.

sprocket .-I8 whose teeth I9 t withinthe spaced tape openings 2G.. Ilhe tape continues from the sprocket around the other set of rollers 23h, ar-

ranged. in spiral fashion, and out through the.

other walljopening I4 onto the exterior of the forward cylindrical wall I2a, where the calendar dates may be viewed.

A cover plate 23 is secured to the housing. This plate has a centralhole 29 to permit free passage of the sprocket shaft `I1`and isalso provided with a plurality of spaced countersunk..

holes .3d through which. suitable screws 3! may extend into threadedholes 32 inlugs 33 .projecting inwardly of the housing wall I2a, to secure thecover 23 rmlytothe housing Ill. The cover plate has a depending arcuate rim li4 extending along the forward wall I2a`. and engaging the upper edge of the tape i5 to connelitagainst Verticalv movement in conjunction with an arcuate rim 35 extending upwardly fromthebase Hand contacting the lower edge ofthe tape. The upper and lower rims 34, 35 define a curved. channel in which the tape I5 is conned along the exterior of the forward wall I2a. Y

The roller racki is angularly adjustable with respect to the housing It to approximately, ten

sion the calendar tape I5. As disclosed in the drawings, the roller rack plate 25 :has a plurality of arcuately arranged holes v. 36 adjacent its periphery, and the housing base I I has a:plurality of,-arcuately lspaced sockets or-holes. 31 aligned with corresponding hoels 3B in the cover plate 28..

The holes Se,v 31, 38 in the rack, base and cover plate have the same diameter, with the .basevand cover plate holes 31, 38 spaced a greater distance apart than the rack holes 36. In the specific example in the drawings, the rack holes are spaced apart from center to center two diameters, while the holes 31, 38 in the base and cover plate are spaced apart from center to center three diameters.

An appropriate tool may be inserted through an arcuate slot 39 in the cover plate into engagementwith the'rack platev '25, and the latter turned clockwise until the appropriate tension is placed on the calendar tape I5. Thereafter, a lock pin lll is inserted through one of the cover plate holes-35, an aligned rack hole St, and into an aligned hole or socket 31 in the base plate, to prevent further angular displacement between the housing Iiland roller rack 26 and hold the tape I5'tensioned around the xed axis roller 2I,rackl.rollers 23a, 23h, forward wall I2a and sprocket I2. The holes are so spaced and disposed that vthe roller rack-.25 can beY moved arcuately any amount within the .limits of the device and one of its holes 36 willalign` with-1a; cover plate hole Sii and base socket 31, permittingA insertion ofthe pinE it through the aligned holes to lock the rack: .in itsy aposition of tensioning. adjustment.

4l-'minimum menstrual cycle band or ring-lll.

encompasses the housing-wall I2a, IZUand cover:

plate 23, anda maximum menstrual cycle disk l2 is disposed voventhev cover plate -28 Aand part` The disk has a central hole 3.to\

tween the ends of the-sprocket IB andthe cover. `plate 2S,.and .base socket I6, and .between the. handle lli -and maximum menstrual cycle disk.` 42...

The cover plate 2B has aplurality of. arcuately arranged indicia. 1 thereon. representing. the number of days of the menstrual cycle. Asspe- Vlciically disclosed in the drawings therdays.. are numbered counterclockwise from 20. tolli), the

indicia or lines being spaced from one anotherw the/same angular distance as. thespacing of the. calendar days on the tape portion engaging the. curved forward wall 52d. The minimum men-.- strual cycle band or ring il has a beveledtab 581.. projected .inwardlyfrom the upper edge over the.. cover plate and provided with a reference arrow` ormark 'gadapted to point to the menstrual cycle 'scale 411. This ring has anextended open. ing 'alongthe forward.housin'gwalll i2a, de'- fined 'by upper and lower sides 5l, 52, withthe... right portion of 'the opening containing. a colored transparent window 53`along part of -its length terminating at a fertility reference mark^ or line 5t on the upper and lower sides of the opens ingii.

rdays on the scale fil. placed on the window portion. 55 immediately to the right of the fertility reference mark 5d, which occupies a space-corresponding.to one calendar.`

day on thetape. This. letter E, when used in.

Aconjunction with the calendar tapein the manner to bedescribed, indicates the earliest datezaty Aviewing, reference windowr 56 .has itsiiange orfoot 51`4 which the next menses cancommence.

suitably securedto the housing base AII, and

extendsrvertically across theextended opening.`

In. the specific device in the drawngth'e. openinglit extendsalong the calendar. tape I5 for 40 days, to correspond with the .provision for The letter E may be.

50 with its upper end received in a peripheral cover plate notch 58. The window opening 56 occupies a space corresponding to one calendar day on the tape l5.

The reference arrow 49 is so disposed on the minimum cycle ring 4| with respect to the letter E as to point to the Same number of days on the menstrual cycle scale Iill as the letter E is disposed over the tape l5 ahead of the reference window 56.

The upper side 5i of the ring opening 5B is provided wtih a band 59, which may be distinctively colored, extending in a clockwise direction from the fertility reference mark 54 a distance corresponding to i9 consecutive days on the calendar tape l5, where the band terminates in another fertility reference mark or line 60, which cooperates with the calendar tape to indicate the .first calendar day of the fertile or conception period. The lower side 52 of the ring opening 50 is also provided with a band 5l, which may be distinctively colored, extending clockwise from the fertility reference line 54 for a distance of 16 days, where an ovulation reference mark or line 82 may be placed to indicate on the calendar tape l5 the first day of the ovulation period. It is to be noted that this ovulation colored band 6I extends clockwise a period of 16 days from the fertility reference line 54, or 3 days less than the fertility band 59 on the other side of the opening 5G.

The maximum cycle disk l2 has its rearward portion 63 of substantially less radius than the radius of the cover plate 28 to expose the menstrual cycle scale lil. lts forward portion S4 has a greater radius than the cover plate, being provided with a depending skirt 55 disposed along the exterior of the minimum cycle band 6l. The disk d2 and its skirt 65 hold the band 4l against vertical movement, with its lower edge in slidable engagement with the base H of the housing l.

The disk 112 also has a reference arrow or mark 66 adapted for cooperative indication with the days of the menstrual cycle scale 4l. rlhe disk skirt 65 has an extended opening 5l whose right end has a transparent window 8, preferably of clear plastic or glass, disposed over the band window 53 and having a width corresponding to the spacing of one day on the calendar tape. The skirt sides Se, 'l0 deiining its opening 61 extend in a clockwise direction from the window 68, terminating in upper and lower ends l'l, 'l2 which provide reference lines or marks. The upper reference mark li is spaced a distance corr responding to ll calendar days from the transparent window 63, whereas the lower reference line l2 is spaced l2 days from the transparent window B8.

The reference arrow or mark 8d on the maximum menstrual cycle disk 42 is so arranged thereon as to point to the number of days on the menstrual cycle scale ill' corresponding to the number of calendar days that the transparent window 68, marked L, is spaced from the refer ence window 5S secured to the housing. Thus, rotary movement of the disk 42 to place the maximum cycle arrow 36 adjacent a particular number of days on the menstrual scale 4l places the window L the same number of days distance around the tape l5 from the fixed reference window 56.

Both the ring 4l and disk 2 are angularly adjustable with respect to each other and to the housing le. The minimum cycle ring 4l may be held in a selected position of adjustment with respect to the housing by a suitable lock device, which, as disclosed in the drawings, includes a leaf spring 13 whose lower end is secured to the inner Wall I2b of the housing by a suitable rivet 14. An intermediate lock pin or plunger 'l5 is secured to the spring and extends outwardly through an enlarged hole 'IB in the rearward wall 12b for engagement with any one of a series of holes Tl provided in and extending along the minimum cycle ring 4l. These holes 77 are spaced from each other a distance corresponding to one day on the calendar tape l5 and menstrual cycle scale 4l. The upper end of the leaf spring comprises a handle 18 extending through an enlarged slot I9 in the cover plate, which has a clockwise extending notch 8D adapted to hold the handle 'i8 of the leaf spring inwardly to mainn tain the lock pin 15 free of the band il and its holes T. The opening '.19 is large enough to permit the leaf spring to be shifted transversely to move the pin l5 in and out of the band holes 11, and the spring 13 may swing on its lower pivot 'M sufficiently to place the han' dle 18 in or out of the notch EN).

The maximum cycle disk may also be locked in any selected position by a similar lock device. As disclosed in the drawings, such device includes a leaf spring 8l having a depending leg 32 suitably secured to the inner rear wall i212 of the housing, as by rivets 83. This leaf spring 8l projects around the upper edge of the wall 2b and has an inwardly extending arm 34 carrying a vertical, upwardly projecting pin ilE adapted to extend through a hole S6 in the cover plate and into engagement with any one of a plurality of arcuately arranged ho-les or sockets 8l in the underside of the disk 42. A handle 8B projects upwardly from the end of the leaf spring 8| through an enlarged opening 89 in the cover plate 28 leading into a smaller notch 9D whose sides may engage the shoulders 9! on the handle in order to hold the leaf spring 8i depressed when the handle 38 is moved clockwise and placed under the sides of the notch 9G, to maintain the pin 85 out of engagement with the disk ft2 and its socket holes 81. However, when the handle 5S is pushed counterclockwise to place the shoulders 9| in the larger transverse opening 89, the leaf spring 8| re-elevates itself to position its lock pin within one of the arcuate sockets 37. The arcuate socket holes 8l are arranged on centered distances corresponding to the spacing of the calendar days on the tape I5 and menstrual cycle scale 4T.

From the foregoing description it will be apparent that the minimum, cycle band or ring 4l may be adjusted until its reference arrow 4S points to the selected number of days on the menstrual cycle scale el, and that the maximum cycle disk 42 may also be turned until its refern ence arrow it points to the selected number of days on the menstrual cycle scale whereupon both the band and disk may be locked in their selected positions.

It has been indicated above that the movement of the minimum cycle band lll to position its reference arrow ii!) in alignment with the particular number of days on the menstrual cycle scale Ill, representing the minimum number of days duration of the menstrual cycle, also places the E window 55 the same number of days along the calendar tape i5 from the fixed reference window 5S. Similarly, the placing of the maximum cycle reference arrow 66 in alignment with a particular number ofv days on the menstrual scale 41 rep- Aof the# ovulation'period on the' tape. idifferenceof one day betweenvthese'tworreferl .enceirn'arks 1h12;

been 'assumed thata Womanhasa minimum men'- resenting theiduration of the :maximum-menstrual;

cycle, Vwilliplace the L referencefvvindow SiiV the, l'

same maximum@ number ciA daysralong theftaper from the'xed'reference Window-562i Accordingly; by: appropriately positioning the minimumi cycle ring lli 'and maximumf cyclefdisk 42?' alongathe menstrual scale (lli, and by shifting thef. tape I' to placethe.` date :at which the precedingfm'enses `ovulation. The proper positioning ofthe-maxiemum diskl L12 `and its depending skirt $5 causes theupper end ll of the skirt adjoining theopen- :ing Gli-'to indicate the end of the fertility or con- -ception period on the tapefl and theend 7270i. theilower side 'It' of the skirt to indicate the end Thereis a In theexample shown in-tlie drawings, it has :strual cycle of- 25 daysand a-maxmum menstrual lcyclefof-27 days; and that her last-menses began' onrDecernber 5. Accordingly, the lock devices 13'V 8V arereleased and the minimum band M- is turned' until the minimum cycle` arrow 4S points to"25 days on the menstrual vscale di; and the maximum cycle disk i2 is turned until its reference -arrow Slpoints to 27 days on thev scale 6l'. The lock-devices 13, 8l are then repositioned to Y' hold the band lll and dislwlZ positively in their respective adjusted positions. The calendar tape I5--is then turned by means of the handle 1M,-Y Whoselmotion is transmitted to the tape through the sprocket "18) until the December 5 indicia isalignedwit'h' thexed reference window 55. This places the-E'Window 55 over the December 30: mark on the calendar tape lgandthefl.. windovvA 58-overthe J anuaryl mark on the calendar tape, which represent the anticipated earliest andlat-v est dates, respectively,` at which the next men-l strual cycle can'begin,

The reference line onf the upper side l-of the band opening 50i-fis at Athe beginning of December 1l, which indicates the first day ofthe v fertility' or conception period.,` Similarly.; the reference'flin'exl'l on' the upper side i'cfthe skirt openingfl is at the en-d or DecemberzZO, vvhiclsrl indicates thexend of theV fertility. period;` AlsoV theflovrerb'andlreference line @Eris at the begin-.- ning of; December. 14, Whichindicates the rlc'egine ning of the' ovulation period, andl the references lineair-on the lower skirt side` 'lll is atthe end; oftDecernber; v19, which .'indicates: the :end of. the

ovulation period.

Thel foregoing example attests to the accuracy of the calculator, since the. beginn-ingofthe fertil-I ity', period ony December ll is 19.fdays aheadof;` Decemberv 30, the anticipated earliest date on'4V which the next menstrual cycle may occur; Sim". ilarly, the end of the fertility period is the close of December 20, or l1 daysy prior to January 1, Whichisnthe last day on Wliichthe next menstrual v cycle might occur. The: ovulationperiodwill bef. gin` no earlier than December 14, or 3 days afterl thez-.datefon which the fertility periodcan rcom'- meneer andithe; ovulation, period ends awithfthf close ofDecembenl9,or .one dayprlor toithe er1-d'4:

of the fertility perioden-December 20:4

periodfisv 8w days. plus the=irregularity of 2rdays,

lo; 4or a total of 10 days.

The calendar band l5iscontinuoua'with the line gmarkin'gfthefend of December 3l coincid-: ing with the Abeginning of January l of the next year- (see.Y Fig.. 6)', to permit rotation of the` '-15 sprocket l'liinthesame direction .in feeding .the

calendar'tapa lcontinuouslyl in the same direction around'- the forward Wall' l2'a` of thel housing;

Although; only 365T equal` daily` divisions are providedlonst-,he-tape#for a normal 365 day year,

0;theftapeealso embodies a short section 93 of a leap `year scalato enable uninterrupteduse of the calculatorY inA February and Marcin and-.also

April;` of a leap year;` As disclosed in Fig'. 6;-ther leap yearscaleil* is'placedfimmediately above g-ga porticn-off'thenormal scaiefand may beviewed through the extended opening 5B1-fin the mini-- mum cycle band 4l'.

The leapyear scale commenceson February/1 29 and runsior -a-suiciently extendedperiod gotalong-v thenormal scale Within the rangeofVv thecalculator to cover events that may commence or ter1ninatein--January, February-March or April oftheleap-year.- In the drawings, the leap year scale 93-runs from February 29 to April v'9;

mary-'29 isdisposed immediately `above March-1 on the normal scale, March l' immediately above March v2 on t'hefnermalvscale; and-so on, each Oli-day of- Marchf and April onfYthe--leap year scale being ,disposedifimmediately-above the nextrsucl ceeding dayf onthenormalscale.

The --calendar tape: is-usedin= arleap yearin.

exactly'the same manner as. inr anormal year;

with the exception that thev leap. year scale 93his read inplace of the:normaliscale` portion therebelowfon any occurrences which begin on February.` 29; or; aA date l.prior thereto andwhich Will extend for asperiod including February 29. Any

o-pccurrences beginning on and after March 1 inra .f leap year may be indicated through .use of the,

normal scale.v

fertility and ovulation bands 59, 6l from' the E ivindovv 5'5 or-,fferti1ity reference marks .-Eln; and

`valsonopposite tothe ll'fandlZ'zdays spacingiofY thereference marks 7.1,;112 from the L windov/ @8,2

designating theendsof thefertility and ovulaf.. tion periods.`

A modified formxiof the invention is illustrated,` e-n Figs. 9 to y11,. inclusive,` inv which either the minimumcycle banditi-.l ormaximum cycle disk ft2; may. bef` held-y stationary and. .the other moved to accomplish,thee desired-iv results on the,r calcul--r lator.. As. spereiiically shown, the minimum, cyclev wband. fll-` is/,xed .'toz-thehousing. and is provided along its upper side with a plurality of indicia 94- setting forth the minimumy number ofdays of the menstrual' cycle, which may ranger from 20:.-

to 4.0. days Within` the capacity. of the instrument,

751,l running.v ina. .clockwise direction from ,ammi-clayl period to a l0-day period. Each day on the scale 94 extends the same distance as a day on the calendar tape I5. The 2li-day division is 2O days distant from the E window 55, as measured along the tape, and each succeeding division on the scale Q4 is a corresponding daily distance from the E Window.

The maximum cycle disk i2 with its depending skirt 65 is precisely the same as in the other form of the invention.. Although the same maximum cycle scale may be provided on the cover plate 28, Fig. 9 discloses the reference arrow 66a on a beveled portion of the disk pointing to a scale 95 labeled irregularity and numbered from to l0 in a counterclockwise direction. The irregularity is the difference between the maximum menstrual cycle and the minimum menstrual cycle, and in the example disclosed in the drawings, in which a maximum cycle of 27 days and the minimum cycle of 25 days is assumed, the reference marker 6ta points to an irregularity of 2 days. The arrow Eta and scale Si', are so disposed relative to each other as to align the L window Eli with. the E window 55 when the arrow 65a points to zero on the scale.

The fixed reierence Window 5S is omitted from this form of the invention and the mode of operation is somewhat different. Instead of moving the first day of the immediately preceding menstrual cycle opposite the window, as in the other form, the calendar tape l5 is moved until such date is in vertical alignment with the number of days representing the minimum cycle on the xed scale dit. The maximum cycle disk l2 has been adjusted to indicate an irregularity of 2 days, which places the reference marks 5l, 62, 'H 72 appropriately along the calendar tape i5 at the beginning and end of the conception and ovulation periods, and the E and L windows 55, 58 at the potential earliest and latest dates on which the next menses may begin.

In the example disclosed in the drawings, the same set of facts has been assumed, for illustrative purposes, as in the other embodiment. Thus, the calendar tape is moved until December 5 (the first day of menstruation of the period immediately preceding) is aligned with the 25th day indication on the xed minimum cycle scale 94, the maximum. cycle disk 42 having been shifted until its reference arrow 66a points to an irregularity period of 2 days on the irregularity scale 95. This places the reference marks 6l, 'H bounding the fertility period at the beginning of the 11th day and ending on the 26th day, or a period of l0 full days, and the refer-ence marks G2, l2 bounding the ovulation period at the beginning of December 14 and the end of December 19, or a total period oi 6 days. Also, the E` window 55 is disposed over December 30, which is the earliest date at which the next menstrual cycle begin, and the L window di? is disposed over January l, which is the latest date at which the next menstrual cycle may begin.

The irregularity indicator 66a and scale 95 need not be provided on the maximum cycle disk. Instead, as shown in Figs. 12 to 14, inclusive, the maximum cycle indication may be disposed along a beveled peripheral portion 96 of the disk 42 immediately above the indications 94 representing the minimum cycle. The maximum cycle indications 9'! in the example shown in the drawings run in a clockwise direction from 20 to 40 days, with the daily spaces each occupying the same angular distance as the per diem spaces on the calendar tape l5 around the forward wall I2a. This maximum cycle scale 91 is arranged so that the L window B8 coincides with the E window 55 when the irregularity is zero, that is, when the maximum and minimum cycles are equal. Such coincidence of the E and L windows occurs when the disk 42 is turned to place the maximum cycle scale indications 91 exactly coincident with the same indications on the minimum cycle scale 94 immediately therebelow. Any irregularity is reflected through movement of the maximum cycle disk 42 counterclockwise which positions the L window 68 counterclockwise to a later date of potential commencement of the next menses and correspondingly shifts the reference marks Ti, l2, indicating the end of the fertility and ovulation periods, to a later date.

In the operative example disclosed in Figs. 12 to 14, inclusive, the same factors are shown as in the other forms of the invention. That is, the maximum cycle is 27 days, the minimum cycle 25 days, and the date at which the last preceding menses commenced is December 5. The maximum cycle disk d2 is adjusted until the number 27 on its scale 9T is immediately above and in a line with the number 25 on the minimum cycle scale 94. whereupon the disk 42 is locked in such adjusted position. The calendar tape i5 is then shifted until December 5 is in alignment with the number 25 on the minimum cycle scale 94. It is evident that the fertility or conception period then ranges from December ll to December 20, inclusive, the ovulation period from December 14 to December 19, inclusive, the earliest commencement of the next menstrual period is December 30, and the latest date of commencement of such next menstrual period is January 1.

Since the minimum cycle band 4| is stationary in the last two forms of the invention, a releasable lock device need be provided for the maximum cycle disk only. v

By virtue of the present invention, the calculator may be adjusted and locked in adjusted position for any particular woman, depending upon her minimum and maximum menstrual cycles, which requires only movement and positioning of the calendar tape I5 to obtain accurate calendar information regarding her conception and ovulation periods, and the potential earliest and latest dates of commencement of the next menses. In the form of invention disclosed in Figs. l to 8, inclusive, the minimum cycle ring 4| and the maximum cycle disk 47?. are appropriately moved, depending upon the duration of thel minimum and maximum cycles, and are then locked in position. This setting remains xed, requiring only turning of the handle 4l! to move the tape i5 and locate the commencement date of the preceding menses opposite the reference window 56. In the last two forms of the invention, it is only necessary to move one of the menstrual cycle members, such as the maximum cycle disk 42, to a proper position, and then lock it in such position of adjustment. Thereafter, the tape I5 need only be positioned to place the date of commencement of the preceding menses in alignment with the duration time of the minimum menstrual cycle scale 94.

From the foregoing it is apparent that calculators have been devised, which are comparatively easy to operate, and which possess relatively large indicia, oiering greater assurance against inadvertent mis-setting, which would be productive of erroneously indicated results. The large indicia are permitted in View of the relatively y:long t calendar tape, 'f :which,f when'.l divided .f -into :365 equal-parts, still enables i each fpart, or

whaseiplate, said :cylindertbeing fdivided "into first -aandfsecond f sectors-thy @first andisecond periph- .erallyfspaced 'slotseiormedparallcl withthe axis of-fsaid' cylinder; anendless-calendar tapeV eX- derfsector l andfinto said `cylinder means within L-saidzcylinder fori constrainingsaid tape tozmove rin-artortuous path; a :continuous 1annual calendar inscribed on said tape over its entirelength; a "prece'ding menstrualperiodfstarting date 2 indicaftorrmounted'on Vsaid` baserplate `adj acent said first fcylinder lsector and overlying "said 'tape f aV cover :plate "fastened" totheupperendfof '2said'cylinder, rsaidacover 'platerbeing aprovided onits upperf ace with ai menstrual i cycle "scale''periplierally spaced ffr'ornfsaidstartingdateiindicatoriand progressing inthe samf'directiondgf'as saidannual calendar; ".aminimumi'menstrual cycle ^ring v"circumscribing rsaid fcylinder forA rctationthereon,ssaid ring "be- 4ingfprovideld'withaiperipheral slo'tmverlying that `portion` of :said annualf'zcalendar freey'ed laaloout 4'the saidrstfcylinderrsector; a'nextv succeeding mini- ?mumf' menstrual I period marker I provided on said ."rin'g intermediate" the f rendsk ofA said' lperipiieral islet; a'coiiceptionffsector v"indic'zated on the outer -face foi `said=ringradjacent its fsaid'slot,f1said sec- '-to'ri initiating at :said'minimum vmenstrual period lmarker -andextending in 'direction opposite to d, through afdistance equaTto nineteen days as measured ony said annuali calendar;` anfo'vulation Ysector indicated'"onisaid''ringf adjacent-tits said 'slot-,"Tfsaid' ovulation-'sector extending from said minimum menstrual period 'marker' inthe s'ame "direction assaid lconcention'*sector '"iorv fa 'disltaiice lof f'sixteen' days "fasfmea'suredon' said an 'nual "clendar; a minimum" menstrual" cycle "iducial mark indicatedfon'saidi ringin a position to 'taveisefsaid menstrualcycle scale;4 the' distance ''letween f said *next succeeding `minimum menlfstriial4 'peiiod marker' Fand f said minimum men- 'strua'licycl fiducia-l mark measuredin the direc- *tio cl,"bei`ng'suchthatany"given number on said lmc-:iristrual "cycle 'svalev with: which" said minimum 'ienstrual cycld'cial '-'m'ark v:is 'made to register 'uporiithe "rotation of s'aidf minimum menstrual cyclefring'alwaysrepresents the distancein days lieti/veen 4said lpreceding`rrieii'strual period' starting date' indicator'a'nd's'aid i'iext:succeedingmenstrual period marker;` a"ma`Ximum lmenstrual "cycle dislrfmcuntedonI saidcover plate for rota tion Athereon coainallyl Awith said Cylinder and I'provided lwith a skirt overhanging said minimum 'cycle ring, said skirt'beingprovi'ded with a maximum menstrual .period marker overlying said ,annual calendar Aand being .divided' by a peripheralslct also loverlying'said calendar intoiirst andsecond'bands extendingina direction opposite' tod, saidilrst bandbeingfoi a length equal to twelve and said second ,bandfbeing of alength equal to eleven days asmea'sured onthe adjacent portion oi said calendar; a .maximum .menstrual cycle 4ii'ducia'l markindicatedlonlthe 'face of said maximum menstrual 'cycledisk adjacent its peiiph'ery andarrangedto'traverse said menstrual cycle scale,` the .distance-between .said .maximum menstrual .period marker .and said .maximum 5.12 ;linenstrual cycle'iiducialf mark being fsuclr thatfany number on said menstrual cycle scalewith which ::isaid'ducialmarkis made to register ,alwaysaepresentsr the .distancer in days between `saldi-preced- 1 ing'menstrual period'starting date indicator nand zmaximum n'ienstrual period marker; and means for moving said calendar tape so that :.any'fscl'ected'dayfthereon 'can be "broughtfinto registration with saidpreceding `menstrualgperio'd starting date.' indicator.

2..A rhythm calculator-pf @the character described comprising: a `lease4 plate; :an upstanding hollow cylindeiiastened at itsxlower'end'toxsaid base plate, saidcylinder beingidivided intorst and second sectors iby yiirst .and fsecond periph- L'erally spaced slotsiormed'parallel w'ithltheiaxis `oi said cylinder; an upstandingtidler roller' journaled on. saidbase: plate; 'a' roller Arack mountedl in `rsaid 'cylinder Yfor rotationion'` the axis 1 thereof :a

:pluralityof upstanding idler .rollersrmountedfon on its upperiace Vwith a menstrual ','cycle .scale peripherally. spaced iromsaid starting date indicator andzprogressing; inithesame `direction Ydas VsaidA annual :calendar ;f.:a :minimum menstrual .cycle .ring .circumscribingsai'd cylinderxfor rotation "thereon, rsaid .ringfbe'ing provi'ded withfa peripheral slot overlying thatlportionfoffsaid:annual-'calendar .reeved .aboutthe Asaid iirstisector of said cylinder; `ainext succeeding: minimum fmen- .strual period:markerprovided'-on ysaid ring .inter- :mediate "the Nends of :said peripheral: slot; a con- =ception:sectoriindicated on the outer'face olf-'said ring adjacent its v:said slot, saidv sector iinitiating at saidminimum menstrualfperiod marker'fand extendingtin a directionop'positeto said direction d; through an angle equal to that subtended'by nineteen days on 'said annual calendar; .an :ovu-

lation sector indicated-on said'ring adjacent l.its ksaid slot,:.saidovulation sector extending :in `the 'same direction vas `said conception Sector for' 'a distance of -siXteen'days as measured on thel ad- `jacent portionofsaid annual calendar; a minilmum menstrual cycle'i-lducial mark indicated on saidring'and arranged to'traverse said menstrual cycle scale, the distance between said=next succeeding minimummenstrual periodl marker and said menstrual cycle ducial mark measuredin the` direction d, beingfsuch that any given numbei' on said menstrual cyclescalewith vwhich said minimum menstrual cyclafiducial fmark is made to register bythe rotation .offsaid minimum menstrual cycle ring,lalways-.represents theidistan'ce in days lcetweenfsaid` preceding =menstrualfperiod starting date indicator and ysaid -neXt .succeeding; menstrual vperiod marker; -a maximum-Emen- .strual .cycle diskv mounted -.on=said=-.cover plate forvrotation thereon coaxially 'withsaid cylinder and-provided-Awith a-skirt overhanging said minimum cycle l-ring, saidv skirt-.benga provided witha maximum menstrual .period .imarkeroverlyi-ng T said annual calendar,-andl-beingzdividedbylape- 13 ripheral slot also overlying said calendar, into rst and second bands extending in a direction opposite to d, said rst band being of a length equal to twelve days and said second band being of a length equal to eleven days as measured on the adjacent portions of said calendar; a maximum menstrual cycle ducial mark indicated on the face of said maximum menstrual cycle disk adjacent its periphery and arranged to traverse said menstrual cycle scale, the distance between said maximum menstrual period marker and said maximum menstrual cycle ducial mark being such that any number on said menstrual cycle scale with which said ducial mark is made to register always represents the distance in days between said preceding menstrual period starting date indicator and maximum menstrual period marker; and means for rotating said sprocket wheel so that any selected day of said annual calendar can be brought into registration with said preceding menstrual period starting date indicator.

PARK L. MORSE.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 750,226 Ruttman Jan. 19, 1904 1,777,692 Fuss Oct. 7, 1930 1,983,062 Anderson Dec. 4, 1934 2,034,027 Decary et al Mar. 17, 1936 2,127,612 Murguia Aug. 23, 1938 2,134,928 Rahn Nov. 1, 1938 2,343,592 Tilbrook Mar. 7, 1944 2,350,219 Brando May 30, 1944 2,418,207 Tilbrook Apr. 1, 1947 2,465,238 Laux et al Mar. 22, 1949 FOREIGN PATENTS Number Country Date 181,836 Switzerland Apr. 1, 1936 186,871 Switzerland Dec. 16, 1936 395,029 Germany May 14, 1924 

